What Is Ventricular Systole?

Before ventricular contraction. The intraventricular pressure is lower than the intraventricular pressure and the arterial pressure, the atrioventricular valve is opened, the arterial valve is closed, and the ventricle is filled. When the ventricle begins to contract, the intraventricular pressure starts to rise. Pressure, the arterial valve is still closed.

Before ventricular contraction. The intraventricular pressure is lower than the intraventricular pressure and the arterial pressure, the atrioventricular valve is opened, the arterial valve is closed, and the ventricle is filled. When the ventricle begins to contract, the intraventricular pressure starts to rise. Pressure, the arterial valve is still closed.

Chinese name

Ventricular contraction

Foreign name

ventricular systole

Department

Cardiology

Ventricular systole

At this time, the ventricular volume does not change, and the pressure gradually increases, which is called the isovolumic systole, about 0.05 seconds. When the intraventricular pressure exceeds the arterial pressure, the arterial valve opens, and the ventricle begins to eject blood. The ejection period is said to be about 0.02 seconds.

Ventricular systole

(A) atrial systole

When the atrium is dilated, blood from the superior vena cava, inferior vena cava, and coronary sinus flows into the right atrium, and blood from the pulmonary veins flows into the left atrium. Before the atrium begins to contract. The heart is in diastole, the tricuspid and mitral valves are open, and the blood in the atrium flows into the ventricles. After the ventricle is allowed to surplus, the atrium begins to contract. The intra-atrial pressure rises, injecting blood into the ventricle that is already in a full state. The atrial systole was 0.1 s, and then the atria began to dilate.

(B) ventricular systole

After the atria contract, the ventricles begin to contract. The ventricular systole includes an isovolumic contraction phase and an ejection phase, which lasts for 0.3S.

1. Isovolumic contraction phase. It lasts for about 0.05s from the closing of the tricuspid and mitral valves to the opening of the pulmonary and aortic valves. When the ventricles begin to contract, internal pressure rises and blood flows back to the atrium, pushing the tricuspid and mitral valves to close. Under the action of the tendon and papillary muscles, the tricuspid and mitral valves will not turn to the atrium, which will help prevent blood from flowing back into the atrium. At this time, the intraventricular pressure is lower than the pulmonary and aortic pressures, and the pulmonary and aortic valves are still closed. Therefore, the ventricle becomes a closed cavity. Because blood is an incompressible fluid, when the ventricle contracts, the internal pressure increases, and the ventricular volume does not change. Therefore, the phase is called the isovolumetric contraction phase. The isovolumetric contraction phase is characterized by a significant increase in intraventricular pressure and a rapid increase.

2. Shoot blood phase. It is a period of time from the opening of the pulmonary and aortic valves to the time before closing, which lasts about 0.25s. According to ejection speed, it is divided into fast ejection phase and slow ejection phase.

(1) Rapid ejection phase: It is about 1/3 before the ejection phase and lasts for 0.10s. After the isovolumetric contraction phase, when the ventricular pressure exceeds the pulmonary and aortic pressures, the pulmonary and aortic valves open. The ventricular muscles contract strongly, and 2/3 of the total ejection volume is rapidly ejected into the pulmonary artery and the aorta: in the rapid ejection phase, the ventricular volume is significantly reduced, and the intraventricular pressure and the aortic pressure increase sharply.

(2) Slow ejection phase: lasting 0.15s, due to the decrease in intraventricular blood and the weakening of myocardial contractility, the ejection speed slows down and the ejection volume decreases. During the slow ejection phase, the ventricular volume shrinks slowly, and the intraventricular pressure and the aortic pressure gradually decrease.